All documents referred to herein, or the indicated portions, are hereby incorporated by reference herein. No document, however, is admitted to be prior art to the claimed subject matter.
Instruments having a variety of modules within which one or more steps of a multi-step procedure are to be performed are known in the art. A challenge in the design and operation of such instruments is devising a way to efficiently transfer the receptacles within which reactions (e.g., chemical, biochemical or biological) take place (hereinafter “reaction receptacles”) between the different modules of the instrument. Modules within the instrument are often replaced or removed for servicing and then reinstalled, and thus the precise location of a receptacle transfer position can vary and is not known with complete accuracy. Thus, the precise location at which any device or apparatus for transferring reaction receptacles between modules must be positioned may not be accurately known.